Speaker is a common electroacoustic transducer for converting electric energy into acoustic energy, and its sound quality is one of the important indicators for measuring the quality of the speaker. In the existing speaker, especially for the speaker module emitting sound at a lateral side, it will inevitably have the problems of sharp and distorted sound caused by lower resonant point in the front cavity, higher SPL of resonant point, higher THD and so on. In order to achieve a euphonic sound quality, the SPL (sound pressure level) corresponding to Fh cannot be too high. Otherwise, the sound will be sharper at Fh, thus affecting the sound effect of the entire speaker module.
In order to reduce the SPL corresponding to Fh, it is common practice to increase the damping by attaching sound absorbing material in the front cavity of the speaker module or other methods, however, which will correspondingly reduce the SPL in other frequency bands, especially the SPL of the frequency band in the vicinity of f0.